[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE 04 JAN 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N3W 3N30W 7N44W 3N60W 4N80W.
SCATTERED MODERATE CONVECTION FROM THE EQUATOR N 6N BETWEEN
25W-45W.

...DISCUSSION...

GULF OF MEXICO...
STRONG MID/UPPER LEVEL RIDGING REMAINS OVER THE GLFMEX WITH AXIS
EXTENDING FROM A ANTICYCLONE OVER THE BAY OF CAMPECHE NEWD OVER
CENTRAL FLORIDA. THE PERSITENT RIDGING CONTINUES TO KEEP
UPSTREAM DISTURBANCE N OF THE AREA AND LIMIT THE INSTRUSION OF
CONTINENTAL AIR. A MIDDLE TO UPPER LEVEL MOISTURE PLUME IS NOTED
IN WATER VAPOR IMAGERY RIDING UP AND OVER THE GLFMEX RIDGE.  AS
A RESULT...SIGNIFICANT IS CONFINED N OF THE AREA OVER THE
INTERIOR CONUS LEAVING THE GLFMEX DRY/TRANQUIL.  AT THE
SURFACE...HIGH PRESSURE OVER THE W ATLC IS PRODUCING YET ANOTHER
DAY OF BRISK ELY FLOW OVER S FLORIDA AND THE SE GLFMEX WITH
MODERATE RETURN FLOW OVER THE W GULF.  THIS PATTERN HAS REMAINED
NEARLY UNCHANGED FOR OVER A WEEK BUT NUMERICAL GUIDANCE
INDICATES A COLD FRONT WILL FINALLY PENETRATE THE AREA WED INTO
THU WITH THE SURFACE RIDGE SLIDING SWD OVER FLORIDA.  THIS
PATTERN SHOULD PRODUCE INCREASING WINDS BEHIND THE FRONT THU
WITH DECREASING WINDS OVER THE REMAINDER OF THE AREA.
CLOUDINESS AND SHOWERS/THUNDERSTORMS WILL ALSO BE ON THE
INCREASE OVER THE NW GLFMEX AS THE FRONT EMERGES OFF SE TEXAS
EARLY THU.

CARIBBEAN...
THE AREA REMAINS UNDER THE INFLUENCE STRONG MIDDLE TO UPPER
LEVEL TROUGH EXTENDING FROM THE ATLC OVER HISPANIOLA TO CENTRAL
AMERICA NEAR COSTA RICA.  STRONG SUBSIDENCE OVER THE CONFLUENT
SIDE OF THE UPPER TROUGH BLANKETS THE HALF OF THE CARIBBEAN
PRODUCING DRY/STABLE CONDITIONS ABOVE 800 MB.  WEAK UPPER LEVEL
DIFFLUENCE EXIST OVER THE E CARIBBEAN CONTRIBUTING TO AN AREA OF
SHOWERS/THUNDERSTORMS ALONG A WEAK LOW LEVEL ELY DISTURBANCE.
THE STRONGEST/MOST NUMEROUS OF THIS ACTIVITY IS CONFINED S OF
15N E OF 60W WITH TYPICAL TRADE WIND SHOWERS ELSEWHERE OVER THE
E CARIBBEAN.

ATLANTIC...
MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE GLFMEX OVER CENTRAL
FLORIDA TO THE W ATLC BEYOND BERMUDA.  THE SUBTROPICAL JET AND
ASSOCIATED MOISTURE LIES ALONG THE N PERIPHERY OF THE RIDGE
CREATING A SHARP DELINEATION IN MOISTURE ALONG THE RIDGE AXIS.
CONFLUENT FLOW S OF THE AXIS IS GENERATING DRY/STABLE CONDITIONS
WHICH EXTENDS EWD ACROSS THE CENTRAL ATLC TO A LARGE UPPER LOW
NEAR 30N48W. AN UPPER TROUGH TRAILS SWD FROM THE LOW INTO THE
CARIBBEAN OVER HISPANIOLA. ENHANCED INSTABILITY ASSOCIATED WITH
THE COLD CORE LOW IS GENERATING SCATTERED MODERATE CONVECTION
OVER THE N PORTION OF THE AREA N OF 28N BETWEEN 36W-50W.  AT THE
SURFACE...A 1012 MB LOW IS LOCATED NEAR 27N49W WITH A BROAD
TROUGH TRAILING SWD ALONG 17N50W TO TRINIDAD/TOBAGO.  SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE OBSERVED WITHIN SEVERAL
DEGREES EITHER SIDE OF THE BOUNDARY WITH BROKEN STRATOCUMULUS
CLOUDS AND WIDELY SCATTERED SHOWERS ELSEWHERE TO 65W.  OVER THE
E ATLC...A LARGE CUTOFF LOW IS LOCATED ALONG THE COAST OF W
SAHARA IN AFRICA WITH ASSOCIATED SUBSIDENCE OVER THE CANARY
ISLANDS AND ATLC WATERS N OF 20N E OF 30W.  FURTHER S...A BROAD
MIDDLE TO UPPER LEVEL RIDGE EXTENDS NWD FROM THE TROPICAL ATLC
ALONG 40W TO BEYOND 32N33W. A SUBTROPICAL JET ALONG THE N
PERIPHERY IS PRODUCING ENHANCED ITCZ ACTIVITY BETWEEN 25W-45W.

$$
RHOME




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